Transistor device



July 24, 1962 R, EMEls 3,046,405

TRANSISTOR DEVICE Filed Jan. 19, 1959 States Patent Ce Y 3,046,405 Patentedr July 24, 1962 VMy invention relates to transistors, phototransistors, and related electric semiconductor devices of the junction type. Such devices comprise a usually monocrystalline semiconductor body of extrinsic conductance which 1s fusion-joined with metallic electrode components, the semiconductor substance consisting in most cases of germanium, silicon, or of such substances as indium antimonide, indium arsenide, gallium phosphide or other semiconductor compounds of the type known asy Am BV and formed` in equal atomic proportions of respective elements from the thirdand fifth Bgroups of the periodic system of elements. v

It is an object of my invention to provide a transistor device which affords a much greater sensitivity lor amplication than heretofore attainable with transistor units of comparable size. y 1

Another object is to devise a transistor device affording plural-stage or multi-stage .amplification within a single structural unit applicable as a circuit component for a great variety of purposes. p l

Still another object ofthe invention is to devise a photoelectric sensing device or phototransistor of extreme sensitivity.

According to my invention, I provide a plurality of individually operable transistors with .a singleisemiconducf tor body and with common collector means such as single collector electrode, the semiconductor body being preferably a at plate 'or Idisc of rectangular or circular shape. Each ofthe transistors has its own base electrodeand emitter electrode, .andthe respective base regionsof the transistors are constituted by partialregions of a single coherent stratum lof the semiconductor body having in that stratum a given uniform type of conductance, namely p-type or n-type, differing from the conductance typevof the semiconductor region adjacent to the collector electrode. The individual emitter electrodes of all transistors me disposed beside the respectivebase electrodes in alternating sequence and are joined with junction-forming semiconductor areas embedded in, or surrounded by, the contiguous base regione'ommon to the combined transistors. l

The base electrodes and the emitterelectrodes of the transistors are'preferably mounted on one of the two ilat sides of theplate or disc of semiconductor material, whereas the common'collector electrode is located on the opposite side of the semiconductor body.

` According to another feature ofV my invention, the base and emitter electrodes of the respective individual transistors are connected with the corresponding electrodes of the other transistors by a cascade network so that the 1 entire transistor combination forms .a plural-stage amplifier. In encapsuled transistor designs the connecting leads between the base and emitter electrodes of the transistors are preferably accommodated Within the housing or capsule so that the entire device forms a single rigid structure. For example, when encapsuling the device by embedding it in a body of casting resin, the semiconductor body and all electrodes, as well as the appertaining terminal leads and cascade connections, are preferably fully embedded in the casting resin so that only the input and output leads emerge therefrom.

ponent of multiplied ampliiication factor.

with three combined transistors, representing a three-stage By virtue of the cascade connection, a transistor unit according to the invention constitutes an amplifying com- For example,

amplification, a single transistor element according to the invention affords obtaining a current amplication of 1110,00() or, as the case may be, results inan extremely sensitiveL photoelectric relay of multipliervv action. Such a plural-stage element is fundamentally applicable in theY same manner as a single transistor to form a component in any desired amplifier combination. This offers l a number of advantages, such as a considerable reduction in space requirements,l mounting requirements, as well as a simplification of the circuit connections and design of the more comprehensivedevices in which the unit is t0 be used.

The invention will be lfurther described with reference to thezembodiments illustrated by way of example on the accompanying drawing, in which Y FIG. 1 shows, on enlarged scale, a cross section of a three-stage transistor according to the invention, with a schematic and explanatory indication of the various conductance regions in the appertaining semiconductor body.

VFIG. 2- is a top view of the same transistor. n FIG. 3 illustrates a top view of a transistor in form of Va rcircular disc, also designed for three-stage amplicacascade in emitter connection,app1ying to transistors as shown in FIGS. 1 to 3.

, FIG;.5 shows in cross ,section a multiple-transistor de-v i vice according-to the invention designedy as a phototran- ".into the originally p-conducting silicon. The base re,

sister. v

FIG.y l6 illustrates a `circuit diagram of the same phototransistor. l s.

The same reference numerals are used in the various villustrations for functionally similar items, respectively.

The semiconductor body 2 in the illustrated embodiments may consist of a silicon plate or disc of which one side is covered by'afoil 3 of a gold-antimony alloy containing, for example, approximately 1% antimony. The foilvformsan lalloyed diffusion bond with thersemiconductor body'Z and serves as a common collector electrode for all transistors of the device. The stratum 4 of the semiconductor body adjacent to the collector electrode 3 is diEusion-dopedrby antimony and thus has n-type con-v ductance. Mounted on the opposite at side of the semi-v conductor body 2 arebase electrode strips 5l and emitter strips V'6 which extend side yby' side in spaced relation to each other in an alternating, sequence. `In the embodiment of FIGS; l and =2, the strip electrodes 5 and Gjarel straight, whereas in the embodiment of FIG. 3 the strips form concentric circles about a centrally located,rcircular base electrode 5.

'.The base strip 5 may consistiof aluminum and the emitter strips 6 of gold-antimony, whose antimony content naly be about 1% as in the case of the collector-electrode o1 together with the silicon body, thus forming a fusion bond. .'As a result each emitter strip 6 is located adjacent i l an antimony-doped local zone 7 of the semiconductorV body 2, so that the emitter regions of the semiconductorare n-conducting. These n-type zones 7 penetrate slightly gions of the respective base electrodes 5 are formed bv partial regions of a coherent p-type stratum in which the silicon body 2 retains its p-type conductance.

The circuit diagram illustrated in FIG. 4shows the internal wiring of the device in emitter connection. The emitter electrode 6 of each preceding transistor stage 1s connected with the base electrode 5 of the next following stage. The signal to be amplified is applied across Y The base and emitter Vstrip electrodes are alloyed terminals lfit) connected to the base electrode of the first stage and the emitter electrode of the last stage, respectively. The load circuit, connecting the collector means common to all transistors with the emitter electrode 6 of the output stage, is shown to comprise a load resistor S and a direct-current source 9. The casing of the device, constituted for example by a block of casting resin, is schematically indicated at 12 by a broken line. C-nly three terminal leads emerge from the casing or block 12 to the outside as is the case with an ordinary singlestage transistor. lf desired, however, all electrode connections may extend out of the casing in Vorder to permit using the same device selectively in casca-de connection, in parallel connection, or in form of Ia combined cascade and parallel connection.

The phototransistor, according to FIGS. 5 and 6 may have a semiconductor bodv in Vform of a plate corresponding to FlGS. 1, 2 or in form of a circular disc as shown in FIG. 3. The design and circuit connection of the phototransistor are essentially as described above, except that the collector electrode 3 is interrupted or apertured in order to permit the ingress of light or other electromagnetic radiation schematically represented at 11. Subjected to the radiation is the iirst stage of the multipletransistor device, whereas the others act as amplifying stages.

With respect to suitable dimensions or manufacture, reference may be had to the copending application of Adolf Herlet, Serial No. 776,323, tiled November 25, 1958, for Power Transistors, now Patent No, 2,924,760 and assigned to the assignee of the present invention. It will be recognized however, that the particular substances strata, each of said transistors having a base electrode and an emitter electrode spaced from each other on the other flat side of said body, the base electrodes and emitter electrodes of all said transistors extending side by side in alternating7 sequence, said base electrodes being joined with said other coherent stratum, and said body having locally limited zones adjacent to said respcctive emitter electrodes, said zones having the same conductance type as said one stratum joined to said collector electrode, conductor means connecting the emitter electrode of each preceding one of said transistors with the base electrode of the next one of said transistors to form a cascade amplilier.

3. A transistor device, comprising a plurality of indi vidually operable junction transistors having a single semiconductor body and a single collector electrode in common, said body having flat shape and having two individually coherent main strata of different conductance types respectively, said collector electrode being joined on one tint side of said body with one of said strata, each of said transistors having a base electrode and an emitter electrode spaced from each other on the other iiat side of said body, the base electrodes and emitter electrodes of all said transistors extending side by side in alternating used and described above or in said copending application `are not essential to the Vinvention proper, and that with respect to the shape and number of its components, a device according to `my invention may be modied in various respects and hence may be embodied in structure and circuitry other than particularly illustrated and described herein, without departing from the essence of the invention and within the scope of the claims annexed hereto.

I claim:

l. A transistor device, comprising a plurality of individually operable triode junction transistors having a single semiconductor body and collector electrode means in common, said collector electrode means being joined with said body, said body having a coherent stratum of a given conducta-nce type, each of said triode transistors having a single base electrode and an emitter electrode joined with said body in spaced relation to each other, the base electrodes and emitter electrodes of all individual transistors extending beside each other on said body in alternating sequence, sa-id base electrodes being all joined with said coherent stratum of said given conductance type, and said body having a plurality of zones of the opposite conductance type adjacent to said respective emitter electrodes.

2. A transmitter device, comprising a plurality of individually operable junction transistors having a single semiconductor body and a single collector electrode in common, said body having flat shape and having two individually coherent main strata of diterent conductance types respectively, said collector electrode being joined on one flat side of said body with one of said sequence, said base electrodes being joined with sa-id other coherent stratum, said body having locally limited zones adjacent to said respective emitter electrodes, said zones having the same conductance type as said one stratum joined to said collector electrode, conductor means connecting the emitter electrode of each preceding one of sa-id transistors with the base electrode of the next one of said transistors to form a cascade amplifier, the one transistor that forms the input stage of said amplifier consisting of a phototransistor.

4. A transistor device comprising a silicon semicon ductor body having a coherent stratum of a given conductance type, collector electrode means joined with said body, a plurality of emitter electrodes and corresponding base electrodes joined with said body and extending beside each other in alternating sequence, each emitter electrode being positioned in spaced relation to one corresponding base electrode and forming with the one base electrode and said common collector means an individually operable junction transistor, said base electrodes being all joined with said coherent stratum of said given conductance type, and said body having a plurality of zones of the opposite conductance type adjacent to said emitter electrodes.

References Cited in the file of this patent UNITED STATES PATENTS 2,660,624 Bergson Nov. 24, 1953 2,663,806 VDarlington Dec. 22, 1953 2,663,830 Oliver Dec. 22, 1953 2,668,184 Taylor et al. Feb. 2, 1954 2,779,877 Lehovec Jau. 29, 1957 2,886,739 Matthews et a1. May 12, 1959 2,892,094 Lehovec June 23, 1959 2,897,295 Zelinka July 28, 1959 r2,924,760 Herlet Feb. 9, 1960 OTHER REFERENCES Bevitt: Transistors Handbook; Prentice-Hall, Inc.;

1956; pp. 149475. (Copy in Div. 54.) 

